1. Field of the Invention
The present invention relates to the valves used in air conditioning systems, and more particularly to a refrigerant service port valve for air conditioners used to convert or “retrofit” legacy refrigeration systems to the use of environmentally more desirable refrigerants having different operating characteristics, in particular, the refrigerant known as HCR188C® (HCR188C is a registered trademark of A.S. Trust & Holdings Inc. of Saipan, M.P.).
2. Description of the Related Art
Chlorofluorocarbons (CFC's), such as dichlorodifluoromethane and monochlorodifluoromethane, were in heavy usage as a refrigerant for use in automotive air conditioners for many decades. The historical dominance of the CFCs had been, in part, due to their advantageous safety features such as incombustibility, high stability, and lower toxicity. However, it was discovered that the use of CFC's over the years has caused ozone layer depletion, an unquestionably negative impact on the global environment. Thus, the production and use of CFC have been gradually reduced and now tend to be abolished totally.
The automotive industry has migrated over to HFCs (hydrofluorocarbon work media) and developed automotive service port valves for the same. However, HFCs have also been implicated in global warming. Hence there has been renewed interest in alternative air conditioning refrigerants, such as hydrocarbon (HC) refrigerants, as exemplified by U.S. Pat. No. 6,336,333, issued Jan. 8, 2002 to Lindgren (commonly known as HC-12a, formerly a registered trademark of OZ Technology, Inc. of Post Falls, Id.) and U.S. Pat. No. 6,902,686, issued Jun. 7, 2005 to Richard H. Maruya, one of the present inventors, and known by the HCR188C trademark noted above.
While HC refrigerants have been approved for use in industrial process refrigeration, the U.S. EPA has not approved its use in automotive refrigerant systems, and its use as a direct replacement for CFC-12 refrigerant in automotive systems is illegal. However, its use as a replacement for HFC-134a is not restricted by the EPA. Nevertheless, the use of flammable hydrocarbon refrigerants in automotive refrigerant systems is illegal under the laws of many of the states of the United States.
In part, safety concerns have revolved around the risk of leakage into the passage compartment of vehicles in the event of a crash and possible flashback and ignition, with the resulting risk of explosion and fire. Consequently, there is a need for a service port for air conditioning refrigerant systems that incorporates safety features that reduce or minimize the risk of refrigerant leakage and that can be used to retrofit existing air conditioning systems for use of HC refrigerants.
Thus, a refrigerant service port valve for air conditioners solving the aforementioned problems is desired.